What doesn’t work for crops may work for endangered lizards

As drought, climate change and increases in soil salinity are causing farmland to become retired in California, the idled lands could provide landscapes for the endangered blunt-nosed leopard lizard (Gambelia sila).

“There has been habitat loss for the species despite it being fully protected under California and federal law,” said Joseph Stewart, lead author on a study published in PLOS ONE that looked at land that would benefit the lizard. “We’re interested in how to recover the species and get it off the endangered species list.”

As part of his PhD thesis at the University of California-Santa Cruz, Stewart and his colleagues synthesized data on habitat preferences to determine which areas the lizards would benefit from in the San Joaquin Desert. They found 600 square kilometers of farmland that could potentially be restored for them.

The blunt-nosed leopard lizard is adapted to the San Joaquin landscape before the introduction of exotic grasses, Stewart said. These grasses make the vegetation denser, causing more difficulty for the lizards to move through. As a result, farmland with sandy, alkaline soils may be less conducive to crops, but it could be perfect for the lizards, particularly in the northern part of their range, since the soil supports less growth of exotic grasses.

“Climate change exacerbates drought conditions,” Stewart said, “and there are indications that some of those northern sites could become suitable for them again.”

Due to ongoing drought, he said, about 2,000 square kilometers of retired farmland may be available over the next three decades, prompting organizations such as the U.S. Fish and Wildlife Service and The Nature Conservancy to consider acquiring these lands to restore habitat.

Restored habitat could benefit other threatened and endangered species in the area as well, he said. Keystone species such as the kangaroo rat (Dipodomys heermanni) would likely be the first to be restored so that they could burrow through exotic grasses on the landscape.

It’s important to first protect habitat that hasn’t been lost, Stewart said, but restoring farmlands could offer new opportunities.

“One next step is more experimentation,” he said, “acquiring agricultural lands and looking at what it takes to bring that back to habitat.”

Header Image: Retired farmlands in the San Joaquin desert may provide an opportunity for habitat restoration for the blunt-nosed leopard lizard. ©Elliot Schoenig